To get the maximum benefit from an Inertial Navigation System (INS), the INS needs to know the distance between the INS center of percussion and a global positioning system (GPS) antenna (receiver). This distance is referred to as the lever arm. The lever arm can be a difficult thing to measure depending on the distance and location of the equipment. For example, installations can exist with lever arms over 100 meters with multiple immovable objects between the INS and GPS. Any error in this measurement will affect the overall performance of the INS and the ability of the INS to screen bad measurements from the GPS, which can affect the integrity of the system.